Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the Universal Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). For example, China is pursuing TD-SCDMA as the underlying air interface in the UTRAN architecture with its existing GSM infrastructure as the core network. The UMTS also supports enhanced 3G data communications protocols, such as High Speed Downlink Packet Data (HSDPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
In a multi-network environment, a need exists for mobile apparatuses to be able to detect transmissions from more than one base station, even when the multiple base stations operate using different network protocols. The ability to detect multiple network transmissions in this way enables a single apparatus to be assigned multiple Universal Subscriber Identity Modules (USIMs), whereby a user may make a phone call or exchange data using different phone numbers.
In some cases, an apparatus may acquire service on two subscriptions using a single radio. Since both subscriptions share a radio, when one subscription is in a connected mode, the other subscription may be out of service (OOS) due to unavailability of the radio resource. In various situations, including mobility related cases, both subscriptions may compete for radio access. Independent system acquisition for each subscription may have limitations which may lead to a high power consumption of the apparatus and increased probability of page loss due to sharing of the radio resource.